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In this paper, the internal and external cancellation phenomena for damped beams subjected to multi-moving loads are investigated in detail. To start, the theory for the vibration of a simply supported beam is revisited by including the effect of damping. For the first time, a simple expression is derived for the free vibration of the damped beam under multi-moving loads. Based on the concept of local minimum, two cancellation conditions are identified. One is the internal cancellation, which relates to the inherent property of the beam and is conventionally known. The other is the newly formulated external cancellation that relates to the number and spacing of moving loads. For comparison, both the resonant condition and the optimal criterion for span length of the bridge are also briefed. By comparing with the classical solution, the present simple expression for the free vibration of the beam is firstly validated. Then the factors affecting the cancellation are investigated against various load cases and damping levels. The results show that external cancellation occurs more frequently due to the increase in the number and spacing of the moving loads. The damping of the beam has a leaking effect on cancellation, in that nonzero vibration may occur, but it is also quickly damped out by damping itself.

Background The exact role of laparoscopic liver resection (LLR) in patients with hepatocellular carcinoma (HCC) and underlying liver cirrhosis (LC) is not well defined. In this meta-analysis, both long- and short-term outcomes following LLR versus open liver resection (OLR) were analysed. Methods PubMed, EMBASE, Scopus and Web of Science databases were searched systematically for randomised controlled trials (RCTs) and propensity-score matched (PSM) studies reporting outcomes of LLR versus OLR of HCC in patients with cirrhosis. Primary outcome was overall survival (OS). This was analysed using one-stage (individual participant data meta-analysis) and two-stage (aggregate data meta-analysis) approaches. Secondary outcomes were operation duration, blood loss, blood transfusion, Pringle manoeuvre utilization, overall and major complications, length of hospital stay (LOHS), 90-day mortality and R0 resection rates. Results Eleven studies comprising 1618 patients (690 LLR versus 928 OLR) were included for analysis. In the one-stage meta-analysis, an approximately 18.7 per cent lower hazard rate (HR) of death in the LLR group (random effects: HR 0.81, 95 per cent confidence interval [C.I.] 0.68 to 0.96; P = 0.018) was observed. Two-stage meta-analysis resulted in a pooled HR of 0.84 (95 per cent C.I. 0.74 to 0.96; P = 0.01) in the overall LLR cohort. This indicated a 16–26 per cent reduction in the HR of death for patients with HCC and cirrhosis who underwent LLR. For secondary outcomes, LLR was associated with less blood loss (mean difference [MD] −99 ml, 95 per cent C.I. −182 to −16 ml), reduced overall complications (odds ratio 0.49, 95 per cent C.I. 0.37 to 0.66) and major complications (odds ratio 0.45, 95 per cent C.I. 0.26 to 0.79), and shorter LOHS (MD −3.22 days, 95 per cent C.I. −4.38 to −2.06 days). Conclusion Laparoscopic resection of HCC in patients with cirrhosis is associated with improved survival and perioperative outcomes.

Although hepatectomy is the mainstay of curative therapy for hepatocellular carcinoma (HCC), post-operative complications remain high. Presently there is conflicting data on the impact of morbidity on oncologic outcomes. We sought to identify predictors for the occurrence of post-hepatectomy complications, as well as to analyse the impact on overall survival (OS) and recurrence-free survival (RFS).We performed a retrospective review of 888 patients who underwent resection for HCC from 2001 to 2016 in our institution.A total of 237 patients (26.7%) developed 254 complications of Clavien-Dindo Grade ≥2. Hepatitis B (p = 0.0397), elevated ASA score (p = 0.0002), higher platelet counts (p = 0.0277), raised pre-operative APRI scores (p = 0.0105) and bloodloss (p 0.0001) were independently associated with the development of complications. After propensity-score matching, 458 patients were compared in a 1:1 ratio (229 with complications versus 229 without). Patients with complications had significantly longer median length of stay (9 days [IQR 7-15] versus 6 days [IQR 5-8], p 0.0001), higher 90-day mortality rates as well as inferior OS (p = 0.0139), but there was no difference in RFS (p = 0.4577). Age (p = 0.0006), elevated Child Pugh points (p 0.0001), microvascular invasion (p = 0.0002), multifocal tumours (p = 0.0002), R1 resection (p = 0.0443) and development of complications (p = 0.0091) were independent predictors of inferior OS.Post-operative morbidity affected both short-term and OS outcomes after hepatectomy for HCC. Hepatitis B, higher ASA scores, elevated preoperative APRI and increased blood loss were found to predict a higher likelihood of developing complications. This may potentially be mitigated by careful patient selection and adopting strict measures to minimise intraoperative bleeding.

Backgrounds/aims This study aims to evaluate the perioperative outcomes of minimally-invasive enucleation (MIEn) of the pancreas versus open enucleation (OEn). Methods This is a retrospective review of 20 consecutive patients who underwent pancreatic enucleation at a single institution. Results Seven patients underwent MIEn, of which 3 were robotic and 4 were laparoscopic. After propensity-adjusted analysis, the only significant difference was a reduced rate of readmissions within 30 days in the MIEn group versus the OEn group [0 vs 4 (30.8%), p=0.0464]. There were no conversions to open in the MIEn group, and median operation time was similar in both groups. There was no difference in median EBL in both groups, and none of the patients in our series required blood transfusions. The overall morbidity rate was 45.0% and the major complication (Clavien-Dindo>2) rate was 15%; which was similar between both groups. Seven (35%) patients had a Grade B/C POPF, and there was no significant difference between the two groups for this. The MIEn group had a shorter median length of stay compared to OEn [5 days (range, 3-24) vs 8.5 days (range, 5-42)] this was not significant on propensity-adjusted analysis (p=0.3195). There was no post-operative 90-day/in-hospital mortality in all 20 patients. Conclusions Our experience demonstrates that MIEn was associated with similar perioperative outcomes and fewer readmissions compared to OEn.

A white neutron beam line using back-streaming neutrons from the spallation target is under construction at China Spallation Neutron Source (CSNS). Different spectrometers, to be installed in the so-called Back-n beam line for nuclear data measurements, are also being developed in phases. The physical design of the beam line is carried out with the help of a complicated collimation system and a sophisticated neutron dump, taking the overview of the neutron beam characteristics into account. This includes energy spectrum, flux and time structure, the optimizations of neutron beam spots and in-hall background. The wide neutron energy range of 1eV-100MeV is excellent for supporting different applications, especially nuclear data measurements. At Endstation#2, which is about 80m away from the target, the main properties of the beam line include neutron flux of 106n/cm2/s, time resolution of a few per mille over nearly the entire energy range, and in-hall background of about 0.01/cm2/s for both neutron and gamma. With its first commission in late 2017, Back-n will not only be the first high-performance white neutron source in China, but also one of the best white neutron sources in the world.

Iatrogenic injury of the hepatic artery is a potential hazard of hepatopancreatobiliary and gastric surgery. Prompt recognition and specialist management is paramount to limit morbidity for the patient. Several reconstruction options have been reported in the literature, but the optimum approach should be tailored to the individual patient bearing in mind variations in anatomy, clinical conditions, and other concurrent operative interventions. We report the case of a successful hepatic artery reconstruction using the gastroduodenal artery as a transposition graft for inadvertent transection of the common hepatic artery during laparoscopic total gastrectomy. In expert hands, the use of the gastroduodenal artery for extra-anatomic reconstruction of the hepatic artery is a safe, feasible, and effective option.

Global Navigation Satellite System (GNSS) radio occultation (RO) is an innovative meteorological remote sensing technique for measuring atmospheric parameters such as refractivity, temperature, water vapour and pressure for the improvement of numerical weather prediction (NWP) and global climate monitoring (GCM). GNSS RO has many unique characteristics including global coverage, long-term stability of observations, as well as high accuracy and high vertical resolution of the derived atmospheric profiles. One of the main error sources in GNSS RO observations that significantly affect the accuracy of the derived atmospheric parameters in the stratosphere is the ionospheric error. In order to mitigate the effect of this error, the linear ionospheric correction approach for dual-frequency GNSS RO observations is commonly used. However, the residual ionospheric errors (RIEs) can be still significant, especially when large ionospheric disturbances occur and prevail such as during the periods of active space weather. In this study, the RIEs were investigated under different local time, propagation direction and solar activity conditions and their effects on RO bending angles are characterised using end-to-end simulations. A three-step simulation study was designed to investigate the characteristics of the RIEs through comparing the bending angles with and without the effects of the RIEs. This research forms an important step forward in improving the accuracy of the atmospheric profiles derived from the GNSS RO technique.

Spinal cord injury (SCI), as one of the common serious spine disorders, often leads to severe neurological dysfunction and even permanent disability, which will cause heavy economical burden for family and society. Currently, selenium-enriched products have an obvious role in the protection and recovery of SCI; however, its protective mechanism is still unclear.In order to explore the protective effect of selenium-enriched supplement (SES) on SCI, the adult rats were randomly divided into sham operation control (SC) group, ischemia-reperfusion model (IM) group and SES pretreatment (ST) group to investigate the change of ciliary neurotrophic factor (CNTF) and its receptor-alpha (CNTF-Ralpha) during SCI in the presence of SES. The rats in IM and ST groups were subjected to the blockage of their abdominal aorta to establish the model of SCI; but the rats in SC group were subjected to sham operation without the blockage of abdominal aorta. The rats in ST group were fed with foods containing SES at the dose of equivalent 5 mg/L selenium in water before blocking their abdominal aorta. After 7 days, the rats were sacrificed to observe the structure of nerve cells through HE staining and the expression of CNTF and CNTF-Ralpha by Western blot, immunohistochemical, and RT-PCR methods, respectively.Both protein and mRNA of CNTF and CNTF-Ralpha were positively expressed in rats from SC group. The mRNA expression levels of CNTF and CNTF-Ralpha in ST group were much higher than SCI model group.SES can execute a protective role in SCI through up-regulating the expression of CNTF and CNTF-Ralpha.

Nutrient depletion in soils adversely affects soil quality and reduces crop yield and consequently poses a potential threat to global food security and agricultural sustainability. With an emphasis on human-induced nutrient depletion, this paper described the causality among soil nutrient depletion, soil quality, crop production, socio-economic variables, and environmental condition. Then, global soil nutrient budgets of nitrogen (N), phosphorus (P), and potassium (K) were estimated for wheat (Triticum aestivum L.), rice (Oryza sativa), maize (Zea mays L.), and barley (Hordeum vulgare) production for the year 2000. As a result, there were unbalanced fertilization with surplus N in some developing countries and insufficient inputs in many developing and all least developed countries. Globally, soil nutrient deficits were estimated at an average rate (kg ha−1 yr−1) of 18.7 N, 5.1 P, and 38.8 K, covering 59%, 85%, and 90% of harvested area in the year 2000, respectively, and annual total nutrient de...

In 1993, a severe epidemic of a new disease of flue-cured tobacco (Nicotiana tabacum) occurred in western Yunnan Province, People's Republic of China. Since then, over 40,000 ha of tobacco have been affected, with an average incidence of ≈15%. Infected plants were stunted, and leaves showed symptoms of vein distortion, vein clearing, mottling, and rounding. Axillary buds sprouted from the main stem of infected plants early and formed lateral shoots, on which other shoots were produced. As a result, the infected plants presented the characteristic “bushy” appearance. Aphid- (Myzus persicae (Sulzer)) and sap-transmission experiments were conducted. In aphid-transmission tests, after an acquisition feeding period of 24 h on diseased tobacco, the shortest test feeding that resulted in infection was 5 min. The causal agent(s) was readily sap-transmissible, but it could not be transmitted from sap-inoculated plants to healthy plants by aphids. Thirty-two species of plants in eleven families were tested by sap-inoculation for infectivity to alternative hosts by the casual agent(s). All the species of Nicotiana tested were infected. All the hosts were restricted to the solanaceae. The symptoms, transmission, and host range of this disease were identical to those of tobacco bushy top disease in Zimbabwe (1). Using umbravirus-specific primers (3), a 550-bp DNA fragment was amplified by reverse transcription-polymerase chain reaction (RT-PCR) from diseased tobacco, whose sequence (GenBank Accession No. AF402620) indicated the occurrence of an umbravirus. The results coincided with the taxonomic status of Tobacco bushy top virus, one of the causal agents of tobacco bushy top disease (1), a tentative species of the genus Umbravirus (2). To our knowledge, this is the first report of tobacco bushy top disease in China and the first report of a large outbreak of the disease outside sub-Saharan Africa. References: (1) L. F. Gates. Ann. Appl. Biol. 50:169, 1962. (2) F. A. Murphy. et al. Page 388 in: Virus Taxonomy: Sixth Report of the International Committee on Taxonomy of Viruses, Page 388, 1995. (3) P. Vercruysse et al. J. Virol. Methods 88:153, 2000.